Trophectoderm biopsy for aneuploidy testing: preliminary observations and ongoing pregnancies

Abstract

OBJECTIVE: To assess initial results following a series of cases utilizing trophectoderm biopsy (TEB) and 24 chromosome mCGH for preimplantation genetic screening (PGS). DESIGN: Retrospective compilation of 24-mCGH blastocyst results from patients undergoing PGS since February, 2009. MATERIALS AND METHODS: Patients considered candidates for IVF and PGS due to prior pregnancy losses and/or unexplained infertility were counseled extensively prior to proceeding. Patients who had fewer than 3 blastocysts were advised not to proceed with PGS. For patients who had 3 or more blastocysts, their embryos underwent TEB on cycle days 5, 6, or 7. Following biopsy, blastocysts were vitrified individually and then sent for 24-mCGH analysis. RESULTS: To date, 17 patients completed 20 IVF/PGS cycles. Of 104 total blastocysts biopsied, 52 (50%) were euploid, 41 (39%) aneuploid and 11 (11%) failed to produce a result. The male/female sex ratio of blastocysts with was 54% and 46% respectively. 8 patients returned for thaw and transfer of euploid blastocysts. 6 patients achieved pregnancy (75%) with 5 ongoing (62.5%). The mean age of this group was 37 to which an average of 1.4 blastocysts were transferred. An implantation rate of 45.5% resulted from the transfer of 11 blastocysts.Tabled 1TEB Outcome Data# Patients8Mean Age37.0Mean # Blasts Trans1.4Blast Survival91.7% (11/12)PR/Trans75.0% (6/8)OG/PR/Trans62.5% (5/8)IMP Rate/Trans45.5% (5/11) Open table in a new tab CONCLUSION: Though preliminary, this compilation of blastocyst PGS suggests the following: 1) a high percentage of normal-appearing blastocysts demonstrate abnormal chromosome results; 2) identifying euploid blastocysts prior to embryo transfer may reduce the number of transfers necessary to achieve a normal pregnancy; 3) euploid blastocysts likely allow for a higher rate of implantation and OG/PR/T when compared to untested blastocysts; and 4) SET of euploid embryos will likely reduce rates of multiple pregnancy arising from FET cycles where 2 or more embryos are typically transferred.